Crystal Structure Of Starch Research Articles

Insight into characteristics in rice starch under heat- moisture treatment: Focus on the structure of amylose/amylopectin

Heat-moisture treatment (HMT) could improve the structure and physicochemical characteristics of rice starch, the structural changes of amylose and amylopectin needed to be further investigated. Hence, the starch, amylose and amylopectin were modified by HMT with different moisture contents (MC). As MC increased, starch granules became irregular, amylose appeared molten while amylopectin was less damaged. The crystal structure of starch was disrupted by HMT. The increase in the double helix structure of amylose exhibited more drastic tendency towards molecular rearrangement than amylopectin did. In addition, the reduced proportion of amylopectin A chain could affect the rearrangement of amylose. The solubility and pasting temperature improved, but the enthalpy decreased. Moderate MC (20 %, 25 %) could enhance the viscosity and dynamic viscoelasticity. HMT promoted the conversion of RDS to RS, which was significantly increased by 85.26 % at HMT-40 %. These findings contributed to a better understanding of the mechanisms by which HMT affected starch.

Regulating the interaction between protein and starch in noodles through heat loss: Used to improve the edible quality of noodles

The impact of heat loss during water-cooling process on the edible quality of cooked noodles currently remains unclear. This study aimed to explore the effects of different water-cooling times (0, 20, 40, 60, 80, 100, and 120 s) on changes in gluten and starch structures and their impact on the sensory evaluation and texture of noodles. Results showed that the control group had a higher core temperature, while the core temperature of the noodles equilibrated with the water temperature after water-cooling for 100 s. Within the range of 20–100 s of water-cooling time, a sudden drop in the core temperature of the cooked noodles caused the gluten conformation to transition toward more compact β-sheets. Surface hydrophobicity decreased, while S-S and hydrogen bonds increased. The microstructure of the noodles became more compact, reducing gaps between protein and starch molecules. Small-angle X-ray scattering and atomic force microscopy analyses demonstrated that gluten chains aggregated after water-cooling, resulting in increased chain width and height. The wheat gluten protein structure transitioned from a disordered state to a random coil. Ultimately, the hardness, springiness, and chewiness of the noodles gradually increased. Water distribution results revealed that the free water content of the noodles increased after 120 s of water-cooling, enhancing the hydration between protein and water molecules but decreasing the noodle texture. According to X-ray diffraction and differential scanning calorimeter analyses, heat loss did not alter the gelatinized starch crystal structure of noodles. Therefore, changes in core temperature were the primary cause of gluten structural changes prior to 100 s of water-cooling. After 120 s of water-cooling, increased hydration between noodle surface gluten and water negatively affected the edible quality of noodles. This study provides theoretical data on noodle edible quality and is of significant practical importance.

Microwave‐assisted treatment for the improvement of rice flour properties and rice flour bread quality

SummaryModification of rice flour by microwave and its effect on bread making performance was evaluated. Rice flour having two different water content (20% and 30%) were exposed to different level of microwave power (600 W, 700 W and 800 W) with 8 min treatment time to assess its influence on amylose content, thermal properties, morphological structure, functional and crystalline structural that affect bread quality. Microwave‐treated rice flour at 600 W showed notable increment in amylose content of 1.03 folds (for both 20% and 30% water content) as compared to untreated rice flour. The microwave treatment destroyed the amorphous region of the rice flour starch, whereas starch crystal structure was slightly increased after treatment. Rice flour maintained its thermal stability even after exposure to high radiation of microwave. The treated rice flour exhibited starch granules with more voids on its surface, indicating the exudation of amylose at higher temperature. The major effect of microwave treatment was observed on the bread for rice flour treated at 800 W with higher specific volume, increase in gas cells pores, softer crumb, low hardness and delayed staling as compared to untreated rice flour. The microwave‐assisted treatment shows a significant potential in improving the rice flour quality led to increase the quality of bread.

The structural and digestive properties of indica rice starch-fatty acid complexes

The structural and digestive properties of indica rice starch-fatty acid complexes and the effects of lipoxygenase on the structural and digestive properties of the complexes were examined in this study. The complexes were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy and Raman spectroscopy. The results showed that indica rice starch had the highest molecular chain order and the highest crystallinity, and the crystallization disappeared after gelatinization, and the formation of indica rice starch-fatty acid complexes promoted the transformation of starch crystal structure from A-type to V-type. Lipoxygenase reduced the regularity of starch molecular crystal structure in the complexes, while enzyme protein improved the order of starch molecular structure in the complexes. The regularity of starch crystal structure in the complexes could improve with the increase of composite temperature and the increase of fatty acid unsaturation. In vitro digestibility and in vitro digestion kinetics showed that the formation of indica rice starch-fatty acid complexes reduced the digestibility of indica rice starch to a certain extent. The RDS content of indica rice starch was 66.42 ± 0.39 %, and lipoxygenase reduced the reduction of rapidly digested starch content during complexes digestion, while enzyme protein increased the content of resistant starch.

Valuation of the significant hypoglycemic activity of black currant anthocyanin extract by both starch structure transformation and glycosidase activity inhibition

The objective of this study was to investigate the impact of anthocyanin-rich black currant extract (BCE) on the structural properties of starch and the inhibition of glycosidases, gathering data and research evidence to support the use of low glycemic index (GI) foods. The BCE induced a change in the starch crystal structure from A-type to V-type, resulting in a drop in digestibility from 81.41 % to 65.57 %. Furthermore, the inhibitory effects of BCE on glycosidases activity (α-glucosidase: IC50 = 0.13 ± 0.05 mg/mL and α-amylase: IC50 = 2.67 ± 0.16 mg/mL) by inducing a change in spatial conformation were confirmed through in vitro analysis. The presence of a 5′-OH group facilitated the interaction between anthocyanins and receptors of amylose, α-amylase, and α-glucosidase. The glycosyl moiety enhanced the affinity for amylose yet lowered the inhibitory effect on α-amylase. The in vivo analysis demonstrated that BCE resulted in a reduction of 3.96 mM·h in blood glucose levels (Area Under Curve). The significant hypoglycemic activity, particularly the decrease in postprandial blood glucose levels, highlights the potential of utilizing BCE in functional foods for preventing diabetes.

Effect of Ethanol Extract of Tea on the Microstructural Features and Retrogradation Characteristics of Glutinous Rice Starch.

The glutinous rice starch (GRS) regeneration process could lead to decreased product quality and shorter shelf life. The purpose of this study was to analyze the effect of an ethanol extract of tea (EET) on the regeneration properties of GRS. The microstructure of starch was determined via scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy was used to determine the microstructure of starch-polyphenol molecular groups, an X-ray diffraction (XRD) instrument was used to determine the starch crystal structure, a differential scanning calorimeter (DSC) was used to determine the thermodynamic properties of starch, and the inhibitory effect of EET on GRS regeneration was comprehensively evaluated. The effect of EET on the in vitro digestion properties of GRS was also determined. The results showed that the addition of EET in GRS resulted in an increase in solubility and swelling power and a decrease in crystallinity and ΔHr. Compared to the control group, when retrograded for 10 days, the ΔHr of GRS with 1%, 2.5%, 5%, and 10% addition of EET decreased by 34.61%, 44.53%, 52.93%, and 66.79%, respectively. Furthermore, the addition of EET resulted in a decrease in the content of RDS and an increase in the content of SDS and RS in GRS. It was shown that the addition of EET could significantly inhibit the retrogradation of GRS, improve the processability, and prolong the shelf life of GRS products.

Effect of Starch Plasticization on Morphological, Mechanical, Crystalline, Thermal, and Optical Behavior of Poly(butylene adipate-co-terephthalate)/Thermoplastic Starch Composite Films.

Starches plasticized with glycerol/citric acid/stearic acid and tributyl 2-acetylcitrate (ATBC), respectively, were processed with poly (butylene adipate-Co-terephthalate (PBAT) via extrusion and a film-blown process. All the composite films were determined for morphology, mechanical, thermal stability, crystalline, and optical properties. Results show that the most improved morphology was in the 30% glycerol plasticized PBAT/thermoplastic starch (TPS) composite films, characterized by the smallest and narrowest distribution of TPS particle sizes and a more uniform dispersion of TPS particles. However, the water absorption of PBAT/TPS composite films plasticized with glycerol surpassed that observed with ATBC as a plasticizer. Mechanical properties indicated insufficient plasticization of the starch crystal structure when using 10% ATBC, 20% ATBC, and 20% glycerol as plasticizers, leading to poor compatibility between PBAT and TPS. This resulted in stress concentration points under external forces, adversely affecting the mechanical properties of the composites. All PBAT/TPS composite films exhibited a negative impact on the initial thermal decomposition temperature compared to PBAT. Additionally, the haze value of PBAT/TPS composite films exceeded 96%, while pure PBAT had a haze value of 47.42%. Films plasticized with 10% ATBC, 20% ATBC, and 20% glycerol displayed lower transmittance values in the visible light region. The increased transmittance of films plasticized with 30% glycerol further demonstrated their superior plasticizing effect compared to other PBAT/TPS composite films. This study provides a simple and feasible method for preparing low-cost PBAT composites, and their extensions are expected to further replace general-purpose plastics in daily applications.

Structural modification of starch and protein: From the perspective of gelatinization degree of oat flour

To clarify the relationship between gelatinization degree and structure characteristics, oat kernels were roasted to different gelatinization degree of 15 %–90 % based on tempering water content of 22.5 %–35 %, and the structure characteristics of starch and protein were evaluated. The results showed that the increased gelatinization degree dependent on tempering water content promoted protein aggregation on the surface of starch particles, forming larger aggregates with molecular weight >100 kDa. Oat kernels presented a dense starch gel network structure induced by gelatinized starch. Partial gelatinization of starch led to a decrease in pasting viscosities (setback viscosity, 3.91 Pa·s–1.59 Pa·s) and enthalpy (5.12 J/g–0.11 J/g). With the increase of gelatinization degree, the starch crystal structure conversed from A + V type to V type, accompanied by the formation of starch-lipid complexes and a decrease of relative crystallinity (22.28 %–8.72 %). Moreover, 50 % gelatinized oat flour possessed the highest β-sheet structure (38.04 %), but a decrease in surface hydrophobicity and an increase in endogenous fluorescence intensity were found in oat flour of gelatinization degree >50 %. This study provided a theoretical reference for the application of oat flour with different gelatinization degrees to match suitable products.

Mechanism of interaction between agar and corn starch: Towards improved properties of starch-based cryogel

In this study, agar/corn starch cryogels with different morphologies and characteristics were synthesized using sol, gel, and freeze-drying techniques. The addition of agar increased the gelatinization temperature of starch and decreased the gelatinization enthalpy, thereby inhibited the gelatinization process of starch. The rheological data revealed that the addition of agar accelerated the gelatinization process of the agar/starch binary system and significantly increased the storage modulus of the hydrogel. Fourier transform infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy demonstrated that agar disrupted the retrogradation and crystal structure of starch. A lower concentration of agar destroyed the network structure formed by starch and increased the pore size of cryogel. However, the fiber-bundle structure formed in the large pores after increasing the agar content made the cryogel network more compact. However, this led to marginal increase in cryogel density which endowed the cryogel with significantly improved compressive strength (5.01 MPa) and toughness. Therefore, the incorporation of agar into starch to prepare a composite cryogel is an effective approach for improving the properties of starch-based cryogels.

Optimizing techno-functionality of germinated whole wheat flour steamed bread via glucose oxidase (Gox) and pentosanase (Pn) enzyme innovation

Germination, a powerful biofortification technique, holds immense potential in bolstering the micronutrient profile of essential staple grains, thereby paving the way for optimal nutritional enhancement. The primary goal of this study was to improve the technological functionality of germinated wheat flour by incorporating pentosanase (Pn) and glucose oxidase (Gox) enzymes, with particular emphasis on the evolutionary changes in its components. The inclusion of Gox did not produce any substantial impact on the volumetric characteristics of the steamed bread. The incorporation of Pn and Gox has been seen to enhance the overall excellence of steamed bread by optimizing loaf volume and textural characteristics while also improving the thermal stability of the dough. The existence of two endothermic peaks could be attributed to bound water or alterations in the granules within the starch crystallization region. Adding Pn and Gox reduced and increased the formation and stability time of the dough, respectively. A certain ratio was employed to assess alternations in the crystallinity of starch granules over a limited range. After steaming, a significant decrease in IR1047/1022 was observed, indicating that the elevated temperature partially disrupted the internal starch crystal structure, leading to a gelatinization reaction with water. The ratio of tensile resistance (R) and elongation (E) of dough increased significantly compared to the control. The results obtained from this study indicate that the simultaneous inclusion of enzymes (Pn + Gox) holds significant promise for expanding the technological functionality of germinated wheat flour dough and improving the quality attributes of steamed bread.

The effect of heat treatment of starch on its crystal structure and dynamic viscosity of starch pastes

Analysis of literature data shows the uncertainty of a number of issues of the starch dextrinization process, namely the patterns of the change in the crystal structure of starch during heat treatment and the dependence of the viscosity of starch pastes of dextrins on the conditions of starch heat treatment. These questions were chosen as the topic of this study. A decrease in the average size of starch particles by 2.7 m and an increase in the intensity of reflexes of diffractograms in the range of 2=10–200 after its heat treatment at 1350C (the temperature at which the dextrinization process starts) are well explained by dehydration and a change in the degree of crystallization of biopolymer macromolecules due to their thermal transformations. The dependence of the dynamic viscosity of hot pastes on their shear rate was studied. The steady shear flow curves showed the presence of dilatant areas as a transition from the Newtonian flow regime to the pseudoplastic flow of starch pastes. It was found that the viscosities of heat-treated starch pastes depend on the processing conditions; the viscosities increase in the following order: starch heat-treated in the presence of an acid catalyst; native starch; starch heat-treated without a catalyst for 5 hours; and starch heat-treated without a catalyst for 2.5 hours. It was proposed to divide dextrins into two separate groups: with an increased and with a reduced degree of amylose polymerization.

Optimization of freezing methods and composition of frozen rice dough reconstituted by glutinous rice starch and gluten

This study investigated the effects of four different freezing methods on the texture of rice dough reconstituted by glutinous rice starch and gluten, and the changes of properties of rice dough with different gluten ratios after liquid nitrogen (LF) treatment. The profiles of frozen rice dough were studied by texture analyzer, low-field NMR, SEM, FT-IR, DSC, CLSM, X-RD and RVA. Results revealed that with the slowing down of freezing rate, the damage of freezing process to starch granules and protein structure in frozen rice dough increases, resulting in the increase of damaged starch, the decrease of protein ordered structure, the change of bound water in frozen rice dough to free water, the decrease of frozen rice dough hardness and elasticity, the decrease of storage modulus (G') and the deterioration of frozen rice dough texture. The addition of gluten in frozen rice dough will increase the short-range ordered structure and crystal structure of starch, reduce the digestibility of starch, and change the viscosity characteristics of frozen rice dough. Based on the experimental results, adding 10 % gluten is more suitable for making frozen rice dough, while LF has the least effect on frozen rice dough texture.

Effects of drying treatment-induced changes in the physicochemical properties of starch on the textural characteristics of Ginkgo seed crisps

Changes in the physicochemical behavior of starch affect texture formation during the processing of Ginkgo seeds. Novel Ginkgo seed crisps come from explosion puffing drying combined with freeze drying (EPD-FD) or from freeze drying combined with explosion-puffing drying (FD-EPD). During EPD-FD, puffing power decreased due to higher tissue resistance, and tighter intercellular connections of starch due to the generation of a new diffraction peak during explosion puffing pre-drying (EPPD). The crystal structure of starch was destroyed during further FD, resulting in low porosity and quality. In the FD-EPD process, freeze pre-drying (FPD) prompted the generation of loose starch particles, crystal structure changes, and large pores and water migration channels. Further, EPD produces a more significant puffing force, which causes greater damage to starch granules and breaks the hydrogen bonds. It forms large pores and high porosity and brittleness, concomitant with a better texture structure.

RETRACTED ARTICLE: Physicochemical characteristics of jagung bose, an ethnic staple food from East Nusa Tenggara, Indonesia

Jagung bose is a typical corn-based staple meal from East Nusa Tenggara Province, Indonesia, which requires a considerable boiling period due to its hardness. After storage for almost one year, this staple food is prepared from the pena' muti' fatu white corn variety. This study aimed to compare the physicochemical properties of jagung bose to whole corn of the pena' muti' fatu variety. Physicochemical properties analysis consisted of amino acids, functional groups, dietary fiber, proximate, crystallinity, starch granule shape, and pasting properties. In this study, the samples of jagung bose and corn of pena' muti fatu were obtained from the natives in East Nusa Tenggara. Jagung bose was prepared by pounding the kernel to remove the pericarp. The samples were ground and analyzed for physicochemical characteristics, and the data were analyzed by t test. The results showed that whole corn and jagung bose had high amylose and crystallinity and revealed an A-type starch crystal structure. The whole corn had more protein, fat, amylopectin, fiber, and ash but lower starch and amylose content than jagung bose. Starch granules of whole corn and jagung bose were polygonal shape with a smooth surface. The pericarp removal and pounding by adding some water resulted in different pasting properties. The peak, final, and breakdown viscosity and pasting and gelatinization temperatures of whole corn were higher than those of jagung bose. The setback viscosity of jagung bose was lower than that of whole corn, which meant the viscosity was maintained high during cooling. The high gelatinization temperature and crystallinity of jagung bose required a long cooking time.

Appropriate microwave improved the texture properties of quinoa due to starch gelatinization from the destructed cyptomere structure.

Texture characteristics of quinoa under microwave (MW) irradiation were studied from the perspective of starch gelatinization. MW reduced the light transmittance and increased the hardness and stickiness of quinoa. Microstructure showed that MW dispersed the vesicular structure of starch aggregates into separate starch particles, resulting in the full hydration of starch and water molecules to form denser network structures. The value of peak viscosity and setback decreased in RVA after MW treatment, but the gelatinization temperature remained stable. DSC further proved that moderate MW treatment could reduce the gelatinization enthalpy of starch and made quinoa accessible to gelatinize. However, XRD showed that the crystal structure of starch was preserved, but the crystallinity increased. Finally, low field NMR showed that moderate MW stimulated the full hydration of starch to form denser network structures, while excessive MW treatment made starch partially gelatinize and form rigid structure, resulting in negative texture properties.

Improvement of buckwheat noodles quality via differential pressure explosion puffing (DPEP): cooking and structural quality

Abstract In order to improve the poor formability and taste, a method of buckwheat noodles via differential pressure explosion puffing (DPEP) pre-gelatinization was developed. The effects of DPEP on gelatinization properties of buckwheat flour was investigated. The textural properties, sensory evaluation, cross section morphology, crystal structure, thermodynamic properties and simulated digestion in vitro of buckwheat noodles were characterized. The results indicated that DPEP treatment was beneficial for the texture properties and sensory evaluation, while the cooking loss rate and broken rate of noodles were reduced to 16.31% and 6.28%. The crystal structure of starch in noodles pretreated via DPEP form a more compact structure and enhanced the water holding capacity. DPEP reduced the digestibility in vitro of the noodles. The level of rapidly digestible starch reduced to 15.6%, slowly digestible starch and resistant starch increased to 21.6% and 62.8%, which made the buckwheat noodles have potential to improve health of diabetics.

Improvement of rice bran modified by extrusion combined with ball milling on the quality of steamed brown rice cake

To improve the quality of brown rice food, rice bran modified by extrusion and ball milling was mixed with semidry ground rice flour to reconstitute brown rice flour, which was applied in steamed brown rice cakes. The physicochemical properties of modified rice bran and brown rice flour were investigated, and the quality of steamed rice cakes was evaluated. Compared with the single ball-milled rice bran, the rice bran modified by a combination of extrusion and ball milling had a smaller particle size (24.79 μm), stronger swelling (4.23 mL/g) and water holding (3.20 g/g) capacity, and higher nutritional value. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) indicated that the crystal structure of starch was destroyed and amylose-lipid complexes were formed during the extrusion of rice bran. The reconstituted brown rice flour had a higher final viscosity and lower breakdown value than semidry ground brown rice flour, resulting in lower hardness, higher springiness of steamed brown rice cakes, and a specific volume that consequently increased by 21.71%. Hence, the processing of extrusion and ball milling effectively enhances the properties of rice bran, and the reconstituted brown rice flour is a prospective material for improving the quality of brown rice food.

The quality of gluten-free bread made of brown rice flour prepared by low temperature impact mill

Our previous work reported that the brown rice flour prepared by low temperature impact mill possessed excellent physicochemical properties. The performance of brown rice flour in making gluten-free bread was further investigated. It was found that the starch crystal structure was destroyed and the damaged starch content increased as the particle size of brown rice flour decreased. The interaction between the starch and water in the model dough and the matrix structures among the endosperm masses were enhanced as the particle size decreased, making the gluten-free dough more viscoelastic. However, dough made with finer flour was too sticky, which limited the expansion of dough. Gluten-free bread prepared with medium-sized brown rice flour had favorable quality characterized by large specific volume, low hardness, numerous and homogeneous gas cells.

Research of destruction of starch crystal structure in cupcakes with improved recipe

The research topics are the hardening process of flour confectionery during storage, accompanied by a complex of complex physical, chemical, colloidal and biochemical processes associated with starch and proteins. It is revealed that scientists use non-traditional herbal supplements in cupcakes, in particular, medicinal plants, seeds, fruits and leaves of nuts, vegetables, fruits, wild berries. In the work, the objects of research were developed according to the author’s recipes: «Sesame», «Moriachok», «Mitsnyi Gorishok», «Osinnii Aromat», «Chornychnyi», «Medok», «Elitnyi» cupcakes, base samples for comparison – premium flour and "Stoluchnyi" cupcake. In the recipe for these cupcakes, part of the wheat flour is replaced with non-traditional raw materials:– «Sesame» (rye flour, powders of blackberry leaves, blueberry, black currant, chamomile flowers, whey, sesame oil);– «Moriachok» (oatmeal, powders of leaves of frangipani, raspberries, ordinary mother, thallus kelp, oil of pumpkin seeds);– «Mitsnyi Gorishok» (buckwheat flour, peppermint, walnut leaf powder, whey, butter and walnut kernels);– «Osinnii Aromat» (cornmeal, powders of St. John’s wort, perforated, linden blossoms, Echinacea purpurea, skimmed milk powder, candied apple and cherry);– «Osinnii Aromat» (buckwheat flour, chicory root powders, tricolor violet flowers, skimmed milk powder, dried blueberries);– «Medok» (corn flour, powders of linden flowers, heart pollen, flower pollen, skimmed milk powder, pumpkin seed oil, natural honey with pollen);– «Elitnyi» (oatmeal, peppermint leaves, beans, propolis, whey, natural honey with propolis).In the course of the study, the X-ray phase analysis method was used on a DRON-UM-1 diffractometer (Russia), and it revealed the degree and types of deformation of the crystal structure of substances. The range of values is determined at reflection angles in the range of 10–30° – diffraction maxima of starch. The retrograde process based on the obtained diffractograms is analyzed and the ability of the used natural additives in cupcakes to extend their shelf life is confirmed. As a result of baking, the destruction of the crystalline structure of starch in the developed cupcake samples was much more intensive compared with the control sample of the «Stolychnyi» cupcake.

Molecular, crystal and physicochemical properties of granular waxy corn starch after repeated freeze-thaw cycles at different freezing temperatures

The study was undertaken to reveal the effects of freeze-thaw cycles at different freeze temperature (−20 °C, −40 °C and −80 °C) and the number of freeze-thaw cycles (3, 6, 12, 18, 24 times) on physicochemical and structural properties of waxy corn starch. The number of pores on the surface of starch granules increased, but there was no significant (P < 0.05) effect on molecular weight, transparency, freeze-thaw stability and the crystal structure of starch after repeated freeze-thaw cycle. But the crystallinity intensity decreased after freeze-thaw cycles treatment and a tiny decrease in onset, peak, conclusion temperature and gelatinization enthalpy were found. The RVA analysis exhibited an increase in gelatinization temperatures and a decrease in breakdown and setback value after freeze-thaw treatment, which manifested an increase in the aging and heat resistance of waxy corn starch paste. However, there was no statistical (P < 0.05) difference between different freeze temperatures at the same number of freeze-thaw cycle on physicochemical and structural properties of starch. The obtained data could be helpful in evaluation of the repeated freeze-thaw treatment of waxy corn starch-based foodstuffs and providing the theoretical basic for revealing the effect of repeated freeze-thaw processes in manufacture applications.